(1) Field of the Invention
The present invention relates to a heat pump apparatus comprising a heat pump circuit composed of an external combustion engine, a radiator through which a first medium heated by a first heat exchanger of the aforesaid engine flows and a cooler through which a second medium cooled by a second heat exchanger of the aforesaid engine flows.
(2) Description of the Prior Art
Example of prior art heat pump apparatus of the abovementioned structure, as shown in FIG. 9, is disclosed in, for example, Published unexamined Japanese Patent Application No. 25901/1986 and described on the 16th line of page 146 to the 17th line of page 147 of "Development of Stirling Engines", a Japanese book, issued by Industrial Investigation Co., Ltd. on July 25, 1982, as a reference.
In FIG. 9, reference numeral 1 illustrates an external combustion engine where working gas, for example, the helium gas at 700.degree. to 1,000.degree. K., goes in and out an inside space of a head-side cylinder of a first displacer piston 3 moving up and down in the high temperature-side cylinder 2, and also intermediate temperature level gas, for example, temperature of 300.degree. to 400.degree. K., goes in and out an inside space of another side cylinder. Reference numeral 4 denotes a low temperature side cylinder having a second displacer piston 5. Low temperature level gas, for example, temperature of 200.degree. to 300.degree. K., goes in and out the inside space of said cylinder 4 where the second displacer piston 5 moves left and right, and moreover, intermediate temperature level gas goes in and out an inside space of another side cylinder. Reference numeral 6 denotes a heater tube for heating the working gas of high temperature level, and a fin 7 is provided outside of the heater tube 6. The heater tube 6 is so made as to be heated by combustion gas of a burner which is not illustrated. Reference numeral 8 denotes a regenerator where high temperature level gas (hereafter referred to as high temperature gas) goes in and out the upper opening and also intermediate temperature level gas goes in and out the upper opening. Reference numerals 9 and 10 respectively denote first heat exchangers where intermediate temperature level gas (hereafter referred to as intermediate temperature gas) radiates heat. Reference numeral 11 denotes a regenerator where intermediate temperature gas goes in and out the left side opening and also low temperature level gas (hereafter referred to as low temperature gas) goes in and out the right side opening. Reference numeral 12 denotes an second heat exchanger. Reference numeral 13 denotes a tube through which low temperature gas flows, and reference numeral 14 also denotes a tube through which intermediate temperature gas flows.
Reference numeral 15 denotes a radiator of heating load-side connected with the first heat exchangers 9 and 10 through a warm water pipe line 16. Reference numeral 17 denotes a cooler of cooling load-side connected with the second heat exchanger 12 through a chilled water pipe line 18.
Reference numerals 19 and 20 are connecting rods respectively connected with piston rods 21 and 22 of the first and second displacer pistons 3 and 5. These rods are so connected with a crank 23 as to rotate by mutually keeping a constant phase angle. The rotation axis 24 of the crank 23 is connected with a motor (not illustrated) as a starter. In addition to rotate the rotation axis 24 in the right direction as shown by the allow, the first and second displacer pistons 3 and 5 can be moved by keeping a constant phase difference. Further, the diameter of the piston rod 22 of the second displacer piston 5 is so constructed as to be larger than that of piston rod 21 of the first displacer pistons 3. Also, reference numeral 25 denotes a crank case which is separated respectively from the cylinders 2 and 4 by partition walls 26 and 27.
According to the heat pump apparatus constituted in the manner as abovementioned, as the first and second displacer pistons 3 and 5 move by keeping a constant phase difference, the temperature is lowered caused by the expansion of low temperature gas inside the head-side space of the low temperature side cylinder 2. And, the low temperature gas of which temperature is lowered acts to absorb the heat of chilled water when the gas passes through the second heat exchanger 12. Thereby, the chilled water of which temperature is lowered is supplied to the cooler 17 of the cooling load-side. That is, output of chilled water is obtained. On the other side, the intermediate temperature gas acts to heat the hot water when the gas passes through the first heat exchangers 9 and 10. The heated hot water is supplied to the radiator 15 of the heating load-side. In other words, output of hot water is obtained. Namely, by giving a predetermined phase difference to the movement of the first and second displacer pistons 3 and 5, the heat pump apparatus generates cycles for pressure variation, expansion and deflation of the working gas in the external combustion engine 1, heat absorption from outside of the engine 1 and heat elimination to the outside of the engine 1.
Also, regarding the external combustion engine 1, operation of the piston can be carried out by the difference of the inside pressure between the cylinder and crank case 25 by suitably setting the section area of the piston rod 21 of the first displacer pistons 3 and the piston rod 22 of the second displacer pistons 5, that is, self-operation of the engine 1 can be achieved.
For the prior art heat pump apparatus abovementioned, the motor connected with the rotation axis 24 is used as a starter for starting the external combustion engine 1. After starting the engine 1, the power supply to the rotation axis 24 is stopped and the rotation axis 24 is moved by self-operation of the external combustion engine 1 at approximately constant rotation speed. Thereby, since the first and second displacer pistons 3 and 5 move a constant frequency, so, the output of chilled and hot water becomes almost constant. That is, the prior art heat pump apparatus has inconvenience of difficulty to adjust the output of chilled and hot water.
Further, though a certain measure of the output of chilled and hot water can be increased and decreased by means of controlling the pressure variation, expansion and deflation of the working gas in the external combustion engine 1 by adjusting the heating volume of heater tube 6, it is apt to occur overheat of the external combustion engine 1 if carried to the extreme heating volume. In contrast with this, it becomes impossible to keep the self-operation of the external combustion engine 1 if the heating volume is too decreased. Therefore, the apparatus has inconvenience of difficulty to adjust the output of chilled and hot water for wide range.
In order to solve the above problems, an object of the present invention is to provide a heat pump apparatus of which output of chilled and hot water can be adjusted for wide range and operation efficiency can be improved.